package com.cby.leetcode.二叉树.LC617;

public class LC617 {

    /**
     * 合并二叉树
     * 自下而上递归，均不为空则new节点并返回
     * @param args
     */

    public static void main(String[] args){
        Solution solution = new Solution();

        TreeNode treeNode = solution.mergeTrees(null, null);


    }

    static class TreeNode{
        int val;
        TreeNode left;
        TreeNode right;

        TreeNode(){}

        TreeNode(int val,TreeNode left,TreeNode right){
            this.val = val;
            this.left = left;
            this.right = right;
        }

        TreeNode(int val){
            this.val = val;
        }


    }

     static class Solution{

        public TreeNode mergeTrees(TreeNode root1,TreeNode root2){
            if(root1 == null)
                return root2;
            if(root2 == null)
                return root1;

            return new TreeNode(
                    root1.val + root2.val,
                    mergeTrees(root1.left,root2.left),
                    mergeTrees(root1.right,root2.right)
            );

        }

    }

}
